SYAS and JWed/Frumster are also my main sources of the term. I wouldn’t necessarily describe it as “Yeshivish but not in learning”.
I have seen people use it in different ways, and that is one way that it is used.
But I have also seen it used to mean “Chareidi/Yeshivish in terms of hashkafa and/or sociological setting but modern religiously”
In other words, someone who went to Yeshivas that are considered Chareidi as opposed to Modern Orthodox and has Chareidi Rabbanim, but watches movies,etc, and/or makes a point of partaking in the secular world (as opposed to someone who works simply because he needs a parnassah or is not the type who can sit and learn all day).